Numerous geodetic surveying devices have been known since antiquity for measuring one or in particular a plurality of target points. The distance and direction or angle from a measuring device to the target point to be measured are recorded as spatial standard data and also in particular the absolute position of the measuring device is detected in addition to any existing reference points.
Generally known examples of such geodetic surveying devices are represented by a theodolite, tachymeters, and a total station, which are also designated as electronic tachymeter or computer tachymeter. A geodetic measuring device of the prior art is described, for example, in published application EP 1 686 350. Such devices have electro-sensory angle and distance measuring functions, which permit a determination of the direction and distance to a selected target. The angle or distance dimensions are ascertained in the interior reference system of the device and must possibly still be linked to an external reference system for an absolute position determination.
In many geodetic applications, points are surveyed by placing specially designed target objects thereon. These typically consist of a plumb stick having a targetable module, for example, a reflector for defining the measurement section or the measurement point. These target objects are targeted by means of a surveying device, a direction and a distance to the objects are determined, and a position of the objects is thus derived.
Similarly to this point measurement, marking of already known target points or of points, the position of which was defined prior to a marking procedure, can be performed. In contrast to the point measurement, in this case, the position or the coordinates of the points to be marked are known and are to be marked. For such a marking procedure, a plumb stick or a surveying rod is conventionally also used, which rod is carried by a user and positioned on a target point. For this purpose, the user can move toward the target position of the target point based on position information generated by the surveying device, wherein the surveying rod is automatically targeted by the surveying device by a second person or by an automatic mechanism assigned to the surveying device. If the target point has been reached, the user can perform a marking of the point.
Modern surveying devices such as a total station for such marking and surveying tasks have microprocessors for digital further processing and storage of detected measurement data. The devices are typically produced in a compact and integrated construction, wherein coaxial distance and angle measuring elements and computer, control, and storage units are normally integrated in a device. Depending on the level of development of the total station, means for motorization of the target optics, for reflector-free route measurement, for automatic target search and tracking, and for remote control of the entire device are integrated.
Total stations known from the prior art also have a radio data interface for establishing a radio link to external peripheral components, for example, to a data acquisition device, which can be implemented in particular as a handheld data logger, remote control unit, field computer, notebook, small computer, or PDA. By means of the data interface, it is possible to output measurement data acquired and stored by the total station for external further processing, to read in externally acquired measurement data for storage and/or further processing in the total station, to input or output remote control signals for the remote control of the total station or a further external component, in particular in mobile field use, and to transfer control software into the total station.
For aiming at or targeting the target point to be surveyed, geodetic surveying devices of this type have, for example, a telescopic sight, for example, an optical telescope, as a targeting apparatus. The telescopic sight is generally rotatable about a vertical standing axis and about a horizontal tilt axis relative to a base of the measuring device, so that the telescope can be aligned on the point to be surveyed by pivoting and tilting. Modern devices can have, in addition to the optical vision channel, a camera, which is integrated in the telescopic sight and is aligned coaxially or in parallel, for example, for acquiring an image, wherein the acquired image can be displayed in particular as a live image on the display screen of the display-control unit and/or on a display screen of the peripheral device used for the remote control—for example, of the data logger or the remote control unit. The optic of the targeting apparatus can have a manual focus—for example, a set screw for changing the position of a focusing optic—or can have an autofocus, wherein the change of the focal position is performed, for example, by servomotors. Automatic focusing apparatuses for telescopic sights of geodetic devices are known, for example, from DE 197 107 22, DE 199 267 06, or DE 199 495 80.